“There is this impulse that we have, this very clearly documented impulse that people everywhere have, to help. It sounds tacky, but when the bottom drops out, when ordinary life is overturned and there’s this upheaval or this disruption—if it’s a natural disaster or even something like this, that there’s ... in the book I call it a ‘civic immune response.’ People do spontaneously help each other, they work together, they collaborate. This whole idea that society falls apart and everyone descends into madness and violence is just not true. And we know that. We have science that shows it.”